Barbecue grills in the form of kettle cookers in which a cover is directly hinged to the kettle by a pair of external hinge means, each one of the pair being located on an opposing side of the kettle, are known in the prior art. Examples are the U.S. patent to Glaser et al. No. 3,611,915 (FIGS 11-13), the U.S. patents to Wiggins Nos. 3,617,022 (FIG. 5) and 3,692,012 (FIG. 5), and the U.S. patent to Linstead No. 3,714,937 (FIG. 2). In some of the grills, the kettle and its cover must both be of the same spherical shape but of somewhat different dimensions, and because of the latter fact they cannot form a tight closure even when brought into their fully closed position. In all four patents just mentioned, the hinges protrude in an inconvenient manner.
Barbecue cookers of the kettle type in which the cover is secured to the kettle by a single external hinge are also known in the prior art. U.S. Pat. No. 3,611,915 to Glaser et al. (FIGS. 1-10 and 14-17) is an example. The external hinge linkage of such cookers is complicated, unattractive in appearance, and inconvenient because of protruding members (such as mounting screws 25, hinges 28 and detents 40 of the Glaser et al. kettle cooker).
Several barbecue grills that are not of the hemispherical of kettle cooker type, but instead have generally vertical side walls, utilize internal hinges comprising an arrangement of two members pivotally attached at top and bottom to the kettle and its cover. Together with connecting portions of the generally vertical walls of the upper and lower halves of the cooker, these members form a quadrilateral linkage that changes shape as the cover is moved from the closed position to partially open position, and then to completely open position. Examples of grills with hinges of this type are the grills with generally rectangular cross-sections that are sold by Neosho Products Company under the trademark "Buddy L" and those that are sold by Sears Roebuck and Co. under the trademark "Kenmore".
Because the walls of the dome-shaped cover of a kettle cooker are curved in both the horizontal and vertical planes that would pass through the respective pivot points of the two pivoted members of such hinges if one attempted to use them with a kettle cooker, the hinges would bind as the curved walls prevented free movement of the links. Such hinges would thus be inoperable with kettle cookers.
Another barbecue grill with generally vertical side walls, shown in U.S. Pat. No. 3,938,493 to Bauer, utilizes a single hinge member on each side of the grill. The hinge is, again, free to pivot only because of the generally vertical side walls of the grill basin, and thus would be inoperable with a kettle cooker.
All the disadvantages of the prior art devices mentioned above are avoided, and important advantages are achieved, with the kettle cooker hinge of this invention.